Surprised by low gas consumption

Maybe I just googled the wrong thing. I just checked again regarding the KfW reference. KFW 100 corresponds to 100 kwh/sqm. With Kfw 70, we are pretty much exactly in the "expectations" of 70% of KfW 100.

I have the heating costs of my parents in mind, for example, 2000-3000 euros annually (built in 2070), so I found our 600 euros totally okay.

Which year of construction? 2070, probably not.

Our installment is 60€, but we voluntarily pay a little more in advance.

1970 of course. Sorry. It's been so long since the last century...

Okay, that can work out well if not much has been done to the house yet. Friends have a semi-detached house with 120m2 from the 80s, where not much has been done so far, and they burn about 3000€ of heating oil every year.

If I were you, I would wait until this winter. However, as I said, I find the consumption actually too high for the year the house was built. But that's just my personal opinion; I'm not an expert and can only compare it to our little house.

Do you know your previously calculated energy values by heart?

5.8 kW heating load, rec. 34.1 W/m²

Trench collector + brine/water heat pump: ~35€ electricity per month for heating + hot water for 160 sqm KFW 55.

In addition: trench collector as DIY project: subsidy 5,500€, costs under 2,500 -> 3,000€ plus ... (of course only if you enjoy and have time to build it yourself). Brine/water heat pump costs similar to air/water heat pump or gas, so I’ll ignore the costs.